Can't connect wireless after reformat

recently, I reformatted a computer for someone who wanted Vista removed (suprise!!)
and reverted back to Windows XP Pro. I must note that the PC she purchased ( from Best Buy ) was an HP a6310n and no disks at all for the chipset drivers nor any other integrated devices. No real problem for a tech, but here after I did the reformat, I tried to install the Netgear wireless card and the software said I needed at least SP1 on there..again no biggie cuz I just hard wired to the net and downloaded all that stuff...

I installed the card and was on the net wireless-ly for a few minutes, after I took computer back to original location in living room, the wireless would not connect, it would show full signal and then no signal, off and on in the same interval, like a blink.

I took it to various locations and still no go, I switched wirelss cards (they have two of the same netgear wirless usb cards) and still no go, different computers even experienced the same problem....

wired with ethernet it works fine, but no wireless at all...it says 70% and above signal strenght at all times, and can always see my network (SSID), but never connects, always when I do IPCONFIG utilities it says its disconnected when I KNOW ITS ON...

Is this a driver of the card issue? if so how the heck did it work for a quick minute..
also when I try and download the update drivers (from Netgears site via link from their software install CD), it says the download is corrupt..

I've been on this for three days now, and have hooked up countless wireless networks and have neverhad this problem persist, it usually takes after a few tries.

please help cuz I cannot get off this project UNTIL they connect...and reverting back to the image of Vista is NOT AN option (which by the way the GEEK SQUAD tech used the ENTIRE 400gb hard drive for installing Vista, charged her for data transfer when in the manifest it says "..customer had no data to transfer", left her with no manuals or drivers for any of her components)